Motor Drive Circuit Layout for Shorted Switch Operation
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Solution Overview
Problem
Conventional drive devices with multiple switches connected to motors experience high likelihood of short circuits, limiting motor functionality when one switch is shorted, preventing bidirectional rotation.
Innovation Solution
A drive device with a configuration of three series-connected switches in one circuit and two series-connected switches in each of the other circuits, along with resistors and a circuit switch, allows for bidirectional motor rotation even when one switch is shorted, using a computer program for short circuit detection based on voltage information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If two switches are connected in series in each circuit as in conventional drive devices, then the circuit structure is simple, but the likelihood of short circuit increases and motor functionality is limited when a switch is shorted
Solution Approach 1:
The patent divides the third circuit into two separate circuits (third circuit and fourth circuit), each with its own switches. This segmentation allows the system to maintain motor bidirectional rotation capability even when one switch is shorted, as the other circuit can still provide the necessary current path. The segmentation transforms a single point of failure into a distributed architecture where redundancy is achieved through functional duplication.
2Device complexity
If two switches are connected in series in each circuit, then the number of switches per circuit is reduced, but the switching frequency increases leading to higher short circuit risk
Solution Approach 1:
By segmenting the third circuit into two separate circuits, the patent distributes the switching operations across more switches. Although each individual switch still switches frequently, the system-level reliability improves because a short circuit in one switch does not prevent bidirectional rotation through the alternative circuit path.
Solution Approach 2:
The patent applies different switch configurations to different circuits: the first and second circuits use two switches in series, while the third and fourth circuits also use two switches in series but are positioned differently in the overall circuit topology. This local differentiation optimizes the balance between switching frequency and short circuit risk for each specific circuit location.
3Reliability
If one switch in the series circuit is shorted, then the current flow is limited to one direction, but adding more switches increases device complexity
Solution Approach 1:
The patent segments the power supply system into four distinct circuits (first, second, third, and fourth circuits) with specific switch configurations. This segmentation creates redundant current paths that ensure motor bidirectional rotation capability is maintained even when one switch is shorted, as the alternative circuits can compensate for the failure.
Solution Approach 2:
The multiple circuits are designed with universal functionality to provide both forward and reverse current paths. Each circuit configuration (with two switches in series) is capable of supporting bidirectional motor rotation, making the system multi-functional and resilient to individual switch failures.
Data Source
AI summary
In a drive device, a first connection circuit, a second connection circuit, and a third connection circuit are connected individually between an input end and an output end. A first motor is connected between a connection node between a first input switch and a first output switch of the first connection circuit and a connection node between a third intermediate switch and a third output switch of the third connection circuit. A second motor is connected between a connection node between a second input switch and a second output switch of the second connection circuit and a connection node between a third input switch and the third intermediate switch of the third connection circuit.